A Pentode Lock-In Amplifier of High Frequency Selectivity

Michels, Walter C.; Curtis, Norma L.

doi:10.1063/1.1769919

Cited by 48 publications

(29 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…During the later 1930s some geophysical and astrophysical experimenters incorporated the principle of lock-in detection into apparatus to observe weak signals against an irremediably noisy background, e.g., observation of the sun's corona in daylight (Skellett, 1940;Hufbauer, 1994) and measurement of light scattered by the upper atmosphere from a searchlight beam Johnson et ah, 1939). The refinement of the lock-in amplifier as a frequencysensitive and phase-sensitive detector was taken on especially by Walter C. Michels and his students at Bryn Mawr College for women (Michels and Curtis, 1941;Michels and Redding, 1948).…”

Section: Microwave Generation and Transmissionmentioning

confidence: 99%

"Swords into ploughshares": Breaking new ground with radar hardware and technique in physical research after World War II

Forman

1995

Rev. Mod. Phys.

View full text Add to dashboard Cite

A survey is offered of applications to fundamental physical research, in the years immediately following World War II, of the instrumentalities developed for radar during that war. Attention is given to radar astronomy and radio astronomy, linear and cyclical accelerators, microwave spectroscopy, molecular beams, nuclear magnetic resonance, electron paramagnetic and ferromagnetic resonance, measurements of resistivity at high frequencies in metals and of second sound in helium II, and to the concepts of information and signal-to-noise ratio as basic to the design and analysis of experiments. In conjunction with this survey, consideration is given to the autonomy of physics as a knowledge-producing enterprise, framed as a question of continuity in research directions. As that question implies a baseline, the survey of postwar applications is preceded by a survey of those prewar directions of physical research requiring the highest available radio frequencies. Some 500 references are given.

show abstract

Section: Microwave Generation and Transmissionmentioning

confidence: 99%

"Swords into ploughshares": Breaking new ground with radar hardware and technique in physical research after World War II

Forman

1995

Rev. Mod. Phys.

View full text Add to dashboard Cite

show abstract

“…An early account of this idea dates back to 1934 [2], when it was used to detect the balanced state of an ac bridge. Subsequent improvements to the electronics by Michels, Curtis and Redding [3,4] resulted in a practical, narrow-band detector of 1 Author to whom any correspondence should be addressed. high sensitivity, now widely known as a lock-in amplifier 2 .…”

Section: Introductionmentioning

confidence: 99%

Stochastic multi-channel lock-in detection

et al. 2014

View full text Add to dashboard Cite

High-precision measurements benefit from lock-in detection of small signals.Here we discuss the extension of lock-in detection to many channels, using mutually orthogonal modulation waveforms, and show how the choice of waveforms affects the information content of the signal. We also consider how well the detection scheme rejects noise, both random and correlated. We address the particular difficulty of rejecting a background drift that makes a reproducible offset in the output signal and we show how a systematic error can be avoided by changing the waveforms between runs and averaging over many runs. These advances made possible a recent measurement of the electron's electric dipole moment (Hudson et al 2011 Nature 473 493).

show abstract

“…damaged was not a musical instrument, but, rather, a scientific instrument called a Lock-In Amplifier (Cosens, 1934;Meade, 1982;Michels and Curtis, 1941;Stutt, 1949) made by Princeton Applied Research in the early 1960s. It was easy to understand and modify.…”

Section: Feedback Delayed Is Feedback Deniedmentioning

confidence: 99%

Big Data is a big lie without little data: Humanistic intelligence as a human right

Mann¹

2017

Big Data & Society

View full text Add to dashboard Cite

This article introduces an important concept: Transparency by way of Humanistic Intelligence as a human right, and in particular, Big/Little Data and Sur/Sous Veillance, where ''Little Data'' is to sousveillance (undersight) as ''Big Data'' is to surveillance (oversight). Veillance (Sur-and Sous-veillance) is a core concept not just in human-human interaction (e.g. people watching other people) but also in terms of Human-Computer Interaction. In this sense, veillance is the core of Human-in-the-loop Intelligence (Humanistic Intelligence rather than Artificial Intelligence), leading us to the concept of ''Sousveillant Systems'' which are forms of Human-Computer Interaction in which internal computational states are made visible to end users, allowing users (but not requiring them) to ''jump'' into the computational feedback loop whenever or wherever they want. An important special case of Sousveillant Systems is that of scientific exploration: not only is (big/little) data considered, but also due consideration must be given to how data is captured, understood, explored, and discovered, and in particular, to the use of scientific instruments to collect data and to make important new discoveries, and learn about the world. Science is a domain where bottom-up transparency is of the utmost importance, and scientists have the right and responsibility to be able to understand the instruments that they use to make their discoveries. Such instruments must be sousveillant systems!

show abstract

A Pentode Lock-In Amplifier of High Frequency Selectivity

Cited by 48 publications

References 5 publications

"Swords into ploughshares": Breaking new ground with radar hardware and technique in physical research after World War II

"Swords into ploughshares": Breaking new ground with radar hardware and technique in physical research after World War II

Stochastic multi-channel lock-in detection

Big Data is a big lie without little data: Humanistic intelligence as a human right

Contact Info

Product

Resources

About